Process for preparing porous silica particles, said particles and uses thereof

Abstract

The present invention relates to a process for preparing a porous silica particle comprising a step that consists in preparing a silica particle comprising a water-soluble pore-forming agent then in removing said pore-forming agent by dissolution. It also relates to the porous silica particles capable of being prepared by this process and to their various uses and applications.

The invention claimed is: 
     
       1. A process for preparing a porous silica particle comprising:
 preparing a silica particle comprising a water-soluble pore-forming agent; and 
 removing said pore-forming agent by dissolution, 
 wherein said silica particle comprising a water-soluble pore-forming agent is prepared from a reverse microemulsion, and 
 wherein said water-soluble pore-forming agent is chosen from the group consisting of cyclodextrins, cyclodextrin derivatives, monosaccharides, oligosaccharides and polysaccharides. 
 
     
     
       2. The process according to  claim 1 , further comprising:
 a) preparing a water-in-oil microemulsion (Ma) containing said water-soluble pore-forming agent; 
 b) adding, to the microemulsion (Ma) prepared in step a), a compound that enables the hydrolysis of a silane-based compound; 
 c) adding, to the microemulsion (Mb) obtained in step b), at least one silane-based compound; 
 d) adding, to the microemulsion (Mc) obtained in step c), a solvent that makes it possible to destabilize said microemulsion; 
 e) recovering silica particles comprising a pore-forming agent which are precipitated during step d); and 
 f) removing, by dissolution, the water-soluble pore-forming agent from the silica particles recovered during step e) to obtain porous silica particles. 
 
     
     
       3. The process according to  claim 2 , wherein said step a) comprises preparing a first microemulsion (M 1 ) into which the water-soluble pore-forming agent is subsequently incorporated. 
     
     
       4. The process according to  claim 3 , wherein said microemulsion (M 1 ) is obtained by mixing together at least one surfactant, at least one cosurfactant, and at least one non-polar or weakly polar solvent. 
     
     
       5. The process according to  claim 3 , wherein a polar solvent is added to the microemulsion after the incorporation of said water-soluble pore-forming agent into the microemulsion (M 1 ). 
     
     
       6. The process according to  claim 2 , wherein each said at least one silane-based compound is of general formula:
   SiR1R2R3R4, 
 in which R1, R2, R3 and R4 are, independently of one another, a hydrogen; a halogen; an amine group; an amide group; an acyl group; a vinyl group; a hydroxyl group; an epoxy group; an isocyanate group; a carboxyl group; a thiol or mercapto group; an acryloxy group such as a methacryloxy group; an optionally substituted, linear or branched, alkyl group having 1 to 12 carbon atoms; an optionally substituted, linear or branched, aryl group having 4 to 15 carbon atoms or an alkoxy group of formula -OR6 with R6 representing an optionally substituted, linear or branched, alkyl group having 1 to 12 carbon atoms. 
 
     
     
       7. The process according to  claim 2 , wherein said compound that enables the hydrolysis of the silane-based compound is a compound chosen from the group consisting of ammonia, potassium hydroxide (KOH), lithium hydroxide (LiOH) and sodium hydroxide (NaOH). 
     
     
       8. The process according to  claim 2 , wherein the solvent that makes it possible to destabilize the microemulsion (Mc) is a polar solvent ethanol, acetone or THF.